Barrett PRC-4090 - Page 151

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BARRETT PRC-4090 TACTICAL HF SDR TRANSCEIVER - INSTALLATION
General Noise Suppression Tips
When searching for sources of noise, some of their characteristics can be help-
ful in identication:
• Petrol engine ignition noise and contact breaker noise is a sharp staccato
‘plop’ varying with engine speed. It is only with this class of noise that the
impulse noise limiter incorporated within some transceivers is effective.
• Noise from other sources generally has a more ‘mushy’ sound. That from
the alternator/generator may only be troublesome over a limited range
of engine speed and can also be inuenced by the state of charge of the
battery.
• The noise from instrument regulators may depend on the battery voltage,
the reading of the instrument and the length of time the system has been
switched on. For this reason, the search for noise sources must be done
thoroughly to prevent noise from apparently reappearing after the instal-
lation has been completed.
• Electric motors generate a ‘whining’ sound. Do not forget to check wind-
screen wipers, electric fuel pumps, heater and air conditioning fans and
other motors which operate only on an intermittent basis.